"(PeteCresswell)" wrote:
I've been trying to buy four refrigerator/freezer thermometers and it's
frustrating how inaccurate/inconsistent they are.

For Instance:

- 4 thermometers of same make/model, hanging on the same rack.

- Alcohol bulb/glass tube - you'd think basic physics...

- Each reads a different temp from 68 to 74 degrees.

Only thing I can think of is that the card behind the glass thingie is
misaligned, but looking at these things, there does not seem to be enough
physical room for those kinds of errors.

Also, at home I have a couple of digital indoor/outdoor thermometers.

Bring the outdoor sensor inside and put it right next to the master part, and
they're a couple degrees different.

Is there any hope at all of finding four thermometers which:

- All read the same temp when placed side-by-side
- Read the correct temp.

What am I missing?

Best way of testing bulb thermometers is insert in water beaker with
stirring mechanism for rapid low. Add ice should be hear 32 degrees. Air
currents can be tricky and scales can slip. +- 1 degree typical variance.
My two outside units are at least 3 degrees off. Can't find easy way to
cal. Some resistors probably need tweaked.

Greg